1. Field
Aspects of the present invention relate to a method of fabricating a polysilicon layer, a thin film transistor using the same, an organic light emitting diode display device including the same, and a method of fabricating the same. More particularly, aspects of the present invention relate to a method of fabricating a polysilicon layer including diffusing a metal catalyst in a buffer layer and crystallizing an amorphous silicon layer into a polysilicon layer using the metal catalyst in the buffer layer, a thin film transistor having the reduced residual metal catalyst and improved characteristics when it is used as a semiconductor layer, an organic light emitting diode display device including the same, and a method of fabricating the same.
2. Description of the Related Art
In general, polysilicon layers have advantages of high electric field effect mobility, applicability to high speed operation circuits, and enablement of complementary metal-oxide semiconductor (CMOS) circuits, and thus, the polysilicon layers are widely used as semiconductor layers of thin film transistors (TFTs). The TFTs using the polysilicon layers are used as active devices of active matrix liquid crystal displays (AMLCDs) and as switching devices and drive devices of organic light emitting diode (OLED) display devices.
Methods of crystallizing an amorphous silicon layer into a polysilicon layer include solid phase crystallization (SPC), excimer laser crystallization (ELC), metal induced crystallization (MIC), metal induced lateral crystallization (MILC), and other similar methods.
Currently, methods of crystallizing amorphous silicon using metal are being widely researched due to an advantage of a lower crystallization temperature and a shorter crystallization time than that of the SPC. Crystallization methods using metal include MIC, MILC, super grain silicon (SGS) crystallization, and other similar methods. However, the above methods of using metal as a catalyst have a contamination problem due to the metal catalyst, and thus, device characteristics of the TFT may deteriorate.